A thread repair assembly is provided. The thread repair assembly comprises a cutting-nut housing including a first axial end, a second axial end and an internal cutting-nut interface, the first and second axial ends each having an opening. The thread repair assembly further includes a cutting nut at least partially enclosed by the cutting-nut housing and including a plurality of cutting threads configured to engage a threaded element when the assembly is urged in a first axial direction and disengage the threaded element when the thread repair assembly is urged in a second axial direction opposing the first axial direction.

The thread generating tool for producing a thread in a workpiece has the following features: a) the tool is rotatable about a tool axis (A), b) the tool has a number n1 of groove generating regions for generating in each case one groove in the workpiece and a number m1 of thread generating regions for generating the thread in the workpiece, c) each of the m thread generating regions is arranged behind one of the n groove generating regions as viewed in an axial projection parallel to the tool axis (A), and has a smaller extent than said groove generating region as viewed in cross section in the axial projection.

The thread generating tool for producing a thread in a workpiece has the following features: a) the tool is rotatable about a tool axis (A), b) the tool has a number n1 of groove generating regions for generating in each case one groove in the workpiece and a number m1 of thread generating regions for generating the thread in the workpiece, c) each of the m thread generating regions is arranged behind one of the n groove generating regions as viewed in an axial projection parallel to the tool axis (A), and has a smaller extent than said groove generating region as viewed in cross section in the axial projection.

A log splitter tool preferably includes a splitter portion and a drive portion. The splitter portion includes a modified cone shape with a concave curved profile formed on a side. A cross section of the cone shape preferably has a twisting three-lobe shape. A helical three-lobe contact thread is formed in the modified cone outer surface. The three-lobe contact thread preferably has angular spacing between each lobe of greater or less than 120-degrees. The three-lobe contact thread preferably has a constant pitch. The size of each thread preferably decreases in size from a bottom of the modified cone to a top of thereof. A top of the modified cone is preferably terminated with a self-drilling tip. The drive portion extends from a bottom of the cone portion. A second embodiment preferably includes a drive shaft rotatably retained in a handle.

A device (20) for root-rolling a thread (T) on an object (O) includes: a body (21), an accumulator piston (24) mounted for sealed sliding movement within a body passageway (22), a coarse adjustment screw (25) threaded onto the body, a Belleville spring stack (26) compressed between the coarse adjustment screw and the accumulator piston, an actuator piston (28A or 28B) mounted for sealed sliding movement within a cylindrical opening (23) in the body, and a thread roll (32) rotatably mounted on the actuator piston. A fine adjustment screw is threaded (33) into a first opening (34) on the body, and communicates with a fluid chamber between the accumulator and actuator pistons. The positions of the coarse and fine adjustment screws may be selectively adjusted to controllably vary the fluid pressure within the chamber. The device may be mounted on a machine tool (35) and selectively moved toward the object to root-roll a thread on the object when the object and device are rotated relative to one another.

A device (20) for root-rolling a thread (T) on an object (O) includes: a body (21), an accumulator piston (24) mounted for sealed sliding movement within a body passageway (22), a coarse adjustment screw (25) threaded onto the body, a Belleville spring stack (26) compressed between the coarse adjustment screw and the accumulator piston, an actuator piston (28A or 28B) mounted for sealed sliding movement within a cylindrical opening (23) in the body, and a thread roll (32) rotatably mounted on the actuator piston. A fine adjustment screw is threaded (33) into a first opening (34) on the body, and communicates with a fluid chamber between the accumulator and actuator pistons. The positions of the coarse and fine adjustment screws may be selectively adjusted to controllably vary the fluid pressure within the chamber. The device may be mounted on a machine tool (35) and selectively moved toward the object to root-roll a thread on the object when the object and device are rotated relative to one another.

An indexable thread forming tap including: a body in a shaft shape; and a tip concentrically and detachably attached to a leading end portion of the body by screw-fastening and rotationally driven around an axial center along with the body for rolling of a female thread, the body being disposed with a screw hole concentrically to the axial center such that a screw shaft disposed on the tip concentrically to the axial center is screwed into the screw hole for the screw-fastening, a leading end surface of the screw shaft being pressed against a bottom surface of the screw hole into close contact with each other by the screw-fastening to integrally fix the tip to the body without the leading end of the body abutting on the tip, the body being disposed with a restraining hole concentrically to the axial center.

An indexable thread forming tap including: a body in a shaft shape; and a tip concentrically and detachably attached to a leading end portion of the body by screw-fastening and rotationally driven around an axial center along with the body for rolling of a female thread, the body being disposed with a screw hole concentrically to the axial center such that a screw shaft disposed on the tip concentrically to the axial center is screwed into the screw hole for the screw-fastening, a leading end surface of the screw shaft being pressed against a bottom surface of the screw hole into close contact with each other by the screw-fastening to integrally fix the tip to the body without the leading end of the body abutting on the tip, the body being disposed with a restraining hole concentrically to the axial center.

A thread forming tap (1) is provided with a male thread portion (3), a groove, and an inside diameter finishing blade (61). A chamfer portion (31) of the male thread portion (3) is provided continuous with the complete thread portion (32) and decreases in diameter toward a tip end. The groove is provided parallel to a shaft center spanning the complete thread portion (32) and the chamfer portion (31) so as to divide a thread (71) of the male thread portion (3). On the chamfer portion (31) and the complete thread portion (32), the inside diameter finishing blade (61) is provided along an open edge of the groove on the side opposite the rotational direction of the thread forming tap (1). The inside diameter finishing blade (61) cuts and removes a crest portion of the female thread formed on a surface layer of a pilot hole (90). The height of a first step finishing blade (611) of the inside diameter finishing blade (61) on the chamfer portion (31) is lower than the height of a second step finishing blade (612) of the inside diameter finishing blade (61) formed on a portion corresponding to a thread (71) on the tip-most end of the complete thread portion (32).

A thread forming tap (1) is provided with a male thread portion (3), a groove, and an inside diameter finishing blade (61). A chamfer portion (31) of the male thread portion (3) is provided continuous with the complete thread portion (32) and decreases in diameter toward a tip end. The groove is provided parallel to a shaft center spanning the complete thread portion (32) and the chamfer portion (31) so as to divide a thread (71) of the male thread portion (3). On the chamfer portion (31) and the complete thread portion (32), the inside diameter finishing blade (61) is provided along an open edge of the groove on the side opposite the rotational direction of the thread forming tap (1). The inside diameter finishing blade (61) cuts and removes a crest portion of the female thread formed on a surface layer of a pilot hole (90). The height of a first step finishing blade (611) of the inside diameter finishing blade (61) on the chamfer portion (31) is lower than the height of a second step finishing blade (612) of the inside diameter finishing blade (61) formed on a portion corresponding to a thread (71) on the tip-most end of the complete thread portion (32).